Excitation power supply device and detection equipment for photovoltaic string EL detection in photovoltaic power station

Abstract

The utility model discloses an excitation power supply device for photovoltaic string EL detection in a photovoltaic power station, which comprises a control mechanism, and a generator, an AC / DC converter and a charging and discharging mechanism which are sequentially connected, and the charging and discharging mechanism comprises a capacitor charging electronic switch, a high-voltage capacitor and a capacitor discharging electronic switch. The control mechanism is used for controlling the capacitor charging electronic switch to charge the high-voltage capacitor and controlling the capacitor discharging electronic switch to discharge the high-voltage capacitor, and the high-voltage capacitor is connected in parallel between the AC / DC converter and the photovoltaic string. The excitation power supply device for photovoltaic string EL detection in the photovoltaic power station is small in size, light in weight and convenient for field operation; the intermittent power supply mode is small in overall energy consumption and good in energy-saving and emission-reducing effect; the instantaneous output energy is adjustable, and the device is suitable for different types of photovoltaic modules.

Description

Technical Field

[0001] The utility model belongs to the technical field of photovoltaic detection and power supply facilities, and specifically relates to an excitation power supply device for causing a photovoltaic string to generate an electroluminescence (EL) effect and then perform EL detection of the photovoltaic string, and a detection device including the excitation power supply device. Background Art

[0002] Electroluminescence (EL) is a phenomenon that converts electrical energy into light energy. When current is applied to the photovoltaic cells of photovoltaic modules, they emit near-infrared light with a peak spectrum of 1100nm. EL detection of photovoltaic modules can be achieved by taking near-infrared images with a highly sensitive near-infrared camera. EL detection is an important method for quality inspection of photovoltaic modules. It can detect defects that cannot be identified under visible light, such as cracks, fragments, cold solder joints, broken grids, mixed gears and PID in photovoltaic modules.

[0003] When conducting EL testing, it is necessary to provide a forward current to the cells of the photovoltaic module. Usually, the current value is that the short-circuit current Isc of the photovoltaic module is greater than 10A. A single photovoltaic module is composed of 60 or 72 photovoltaic cells in series. The forward voltage drop of each cell is about 0.6V, so the output power of the EL power supply to excite the single-chip module should be more than 400W. The photovoltaic modules in the photovoltaic power station are connected to the photovoltaic inverter in the form of strings. Each string contains 20 to 30 photovoltaic modules connected in series. In order to achieve EL testing without disassembly of the components, a string excitation method must be adopted, and the power supply power reaches more than 8000W. On-site testing of photovoltaic power stations requires the use of generators for power supply. The weight and volume of high-power generators and power supply equipment are relatively large, and the convenience of transfer and endurance are not good, which affects the efficiency of string EL testing at the power station site. Utility Model Content

[0004] In view of this, in order to overcome the defects of the prior art, the purpose of the utility model is to provide a lightweight excitation power supply device for EL detection of photovoltaic strings in photovoltaic power stations.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] An excitation power supply device for EL detection of photovoltaic strings in a photovoltaic power station comprises a control mechanism and a generator, an AC-DC converter and a charging and discharging mechanism connected in sequence, wherein the charging and discharging mechanism comprises a capacitor charging electronic switch, a high-voltage capacitor and a capacitor discharging electronic switch, wherein the control mechanism is used to control the capacitor charging electronic switch to charge the high-voltage capacitor and to control the capacitor discharging electronic switch to discharge the high-voltage capacitor, wherein the high-voltage capacitor is connected in parallel between the AC-DC converter and a photovoltaic string array. A photovoltaic string array is composed of a plurality of photovoltaic strings.

[0007] According to some preferred implementation aspects of the utility model, it includes an output distribution mechanism for connecting to different photovoltaic strings, the output distribution mechanism includes a plurality of output distribution switches electrically connected to different photovoltaic strings, and the plurality of output distribution switches are connected in parallel.

[0008] According to some preferred implementation aspects of the utility model, a first circuit and a second circuit are arranged between the AC-DC converter and the photovoltaic string array, the first circuit and the second circuit are electrically connected to the two ends of the photovoltaic string, respectively, the high-voltage capacitor is connected in parallel between the first circuit and the second circuit, and the capacitor charging electronic switch, the capacitor discharging electronic switch and the output distribution switch are respectively connected to the first circuit or the second circuit.

[0009] According to some preferred implementation aspects of the present invention, the output distribution mechanism is connected between the capacitor discharge electronic switch and the photovoltaic string.

[0010] According to some preferred implementation aspects of the utility model, the capacitance of the high voltage capacitor is 2000-3000u F.

[0011] According to some preferred implementation aspects of the utility model, the control mechanism includes a central processing unit, an AC / DC conversion control module electrically connected to the central processing unit, a charge and discharge control module, and a distribution control module, the AC / DC conversion control module is electrically connected to the AC / DC converter, the charge and discharge control module is electrically connected to the capacitor charging electronic switch and the capacitor discharging electronic switch, and the distribution control module is electrically connected to the output distribution switch.

[0012] According to some preferred implementation aspects of the present invention, the control mechanism includes a human-machine interface and / or a communication module electrically connected to the central processing unit.

[0013] According to some preferred implementation aspects of the utility model, the generator is a gasoline generator for outputting 220V AC power; an AC-DC conversion circuit is provided in the AC-DC converter for converting the AC power into a DC power supply.

[0014] The utility model also provides a detection device including the above-mentioned excitation power supply device for EL detection of photovoltaic strings in a photovoltaic power station, which also includes a near-infrared camera for EL detection.

[0015] Due to the adoption of the above technical scheme, compared with the prior art, the benefits of the utility model are: the excitation power supply device of the utility model for photovoltaic string EL detection in a photovoltaic power station is small in size and light in weight, which is convenient for on-site operation; the intermittent power supply mode has low energy consumption and good energy-saving and emission reduction effects; the instantaneous output energy is adjustable and is suitable for different types of photovoltaic modules. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 This is a schematic diagram of the structure of a detection device for EL detection of photovoltaic strings in a photovoltaic power station in a preferred embodiment of the utility model;

[0018] In the attached figure, there are generator-1, AC / DC converter-2, capacitor charging electronic switch-3, high-voltage capacitor-4, capacitor discharging electronic switch-5, control mechanism-6, output distribution switch-7, photovoltaic string-8, and near-infrared camera-9. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the technical solution of the present invention, the following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solution in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0020] like Figure 1 As shown, the detection device for EL detection of photovoltaic strings in a photovoltaic power station in this embodiment includes an excitation power supply device for exciting a specified photovoltaic string 8 and a near-infrared camera 9 for capturing the EL near-infrared light of the photovoltaic string and outputting an EL image.

[0021] Among them, the excitation power supply device in this embodiment includes a control mechanism 6 and a generator 1, an AC-DC converter 2, a charging and discharging mechanism and an output distribution mechanism connected in sequence. The generator 1 is a portable 2000W gasoline generator 1, which is used to output 220V AC power; the AC-DC converter 2 is provided with an AC-DC conversion circuit for converting AC power into DC power. Preferably, a 1500W AC-DC conversion circuit is installed inside the AC-DC converter 2 to provide 1500V 1A DC power. The charging and discharging mechanism can realize an intermittent power supply mode. The output distribution mechanism controls the excitation sequence of the output power to the multiple photovoltaic strings 8.

[0022] The charging and discharging mechanism includes a capacitor charging electronic switch 3, a high-voltage capacitor 4 and a capacitor discharging electronic switch 5. The control mechanism 6 is used to control the capacitor charging electronic switch 3 to charge the high-voltage capacitor 4 and to control the capacitor discharging electronic switch 5 to discharge the high-voltage capacitor 4. The high-voltage capacitor 4 is connected in parallel between the AC-DC converter 2 and the photovoltaic string array. The photovoltaic string array is composed of a plurality of photovoltaic strings 8. The capacitor charging and discharging characteristics can be used to output short-term high-power direct current to stimulate the photovoltaic string 8. The capacitance of the high-voltage capacitor 4 in this embodiment is 2500u F.

[0023] The output distribution mechanism includes a plurality of output distribution switches 7 electrically connected to different photovoltaic strings 8 , and the plurality of output distribution switches 7 are connected in parallel.

[0024] In this embodiment, a first circuit and a second circuit are provided between the AC / DC converter 2 and the photovoltaic string 8, the first circuit and the second circuit are electrically connected to the two ends of the photovoltaic string 8, respectively, the high-voltage capacitor 4 is connected in parallel to the first circuit and the second circuit, and the capacitor charging electronic switch 3, the capacitor discharging electronic switch 5 and the output distribution switch 7 are connected to the first circuit or the second circuit, respectively. In this embodiment, the capacitor charging electronic switch 3, the capacitor discharging electronic switch 5 and the output distribution switch 7 are connected to the first circuit, respectively, and the capacitor charging electronic switch 3, the capacitor discharging electronic switch 5 and the output distribution switch 7 are connected in sequence between the AC / DC converter 2 and the photovoltaic string 8.

[0025] The control mechanism 6 in this embodiment includes a central processing unit, an AC / DC conversion control module electrically connected to the central processing unit, a charge and discharge control module, a distribution control module, a human-machine interface and a communication module. The AC / DC conversion control module is electrically connected to the AC / DC converter 2 to control the output voltage and current parameters; the charge and discharge control module is electrically connected to the capacitor charging electronic switch 3 and the capacitor discharging electronic switch 5 to realize the charging and discharging of the high-voltage capacitor 4; the distribution control module is electrically connected to the output distribution switch 7 to realize the control of the output distribution switch 7 corresponding to the specified photovoltaic string 8. The human-machine interface can control and display the control mechanism 6, and the communication module can perform remote control and signal transmission. Preferably, the control mechanism 6 is integrated in the host computer for remote operation.

[0026] The working process of the detection device in this embodiment is briefly described below:

[0027] The generator 1 outputs AC power to the AC / DC converter 2, which converts it into DC power. The output voltage and current of the AC / DC converter 2 are controlled by the control mechanism 6. The control mechanism 6 controls the capacitor charging electronic switch 3 to charge the high-voltage capacitor 4 through the charge and discharge control module according to the capacitor charging requirements. After charging is completed, the control mechanism 6 controls the corresponding output distribution switch 7 to close through the distribution control module according to the position of the photovoltaic string 8 to be tested. The control mechanism 6 controls the capacitor discharge electronic switch 5 to discharge and excite the selected photovoltaic string 8 through the charge and discharge control module according to the short-circuit current value of the photovoltaic module. The near-infrared camera 9 captures the EL near-infrared light of the photovoltaic string 8 and outputs the EL image.

[0028] The advantages of the utility model are: 1. The excitation power supply device is small in size, light in weight, portable and suitable for on-site operations; 2. The intermittent power supply mode has low energy consumption and good energy-saving and emission reduction effects; 3. The instantaneous output energy is adjustable and suitable for different types of photovoltaic modules; 4. It is equipped with a photovoltaic string distribution excitation mechanism to avoid safety accidents caused by human errors.

[0029] The above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with the technology to understand the content of the utility model and implement it accordingly, and they cannot be used to limit the protection scope of the utility model. Any equivalent changes or modifications made according to the spirit of the utility model should be included in the protection scope of the utility model.

Claims

1. An excitation power supply device for photovoltaic string EL detection in a photovoltaic power station, characterized in that: It comprises a control mechanism and a generator, an AC / DC converter and a charging and discharging mechanism connected in sequence, wherein the charging and discharging mechanism comprises a capacitor charging electronic switch, a high-voltage capacitor and a capacitor discharging electronic switch, wherein the control mechanism is used to control the capacitor charging electronic switch to charge the high-voltage capacitor and to control the capacitor discharging electronic switch to discharge the high-voltage capacitor, and the high-voltage capacitor is connected in parallel between the AC / DC converter and the photovoltaic string array.

2. The excitation power supply device according to claim 1, characterized in that: It includes an output distribution mechanism connected between the charging and discharging mechanism and the photovoltaic string array, and the output distribution mechanism includes a plurality of output distribution switches electrically connected to different photovoltaic strings, and the plurality of output distribution switches are connected in parallel.

3. The excitation power supply device according to claim 2, characterized in that: A first circuit and a second circuit are arranged between the AC / DC converter and the photovoltaic string array, the first circuit and the second circuit are electrically connected to two ends of the photovoltaic string, respectively, the high-voltage capacitor is connected in parallel between the first circuit and the second circuit, and the capacitor charging electronic switch, the capacitor discharging electronic switch and the output distribution switch are arranged on the first circuit or the second circuit, respectively.

4. The excitation power supply device according to claim 2, characterized in that: The output distribution mechanism is connected between the capacitor discharge electronic switch and the photovoltaic string.

5. The excitation power supply device according to claim 1, characterized in that: The capacitance of the high voltage capacitor is 2000-3000u F.

6. The excitation power supply device according to claim 2, characterized in that: The control mechanism includes a central processing unit, an AC / DC conversion control module electrically connected to the central processing unit, a charge and discharge control module, and a distribution control module, wherein the AC / DC conversion control module is electrically connected to the AC / DC converter, the charge and discharge control module is electrically connected to the capacitor charging electronic switch and the capacitor discharging electronic switch, and the distribution control module is electrically connected to the output distribution switch.

7. The excitation power supply device according to claim 6, characterized in that: The control mechanism includes a human-machine interface and / or a communication module electrically connected to the central processing unit.

8. The excitation power supply device according to any one of claims 1 to 7, characterized in that: The generator is a gasoline generator for outputting 220V AC power; an AC-DC conversion circuit is provided in the AC-DC converter for converting the AC power into a DC power supply.

9. A detection device for EL detection of photovoltaic strings in a photovoltaic power station, characterized in that: Comprising an excitation power supply device as described in any one of claims 1-8.

10. The detection device according to claim 9, characterized in that: Includes a near-infrared camera for EL inspection.

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